Synthetic lubricating oil compositions



2,837,562 SYNTHETIC LUBRICATING 011. COMPOSITIONS Alfred H. Matuszak, Westfield, Harold R. Ready, Roselle Park, and William E. Lifsou, Union, N.J., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application January 4, 1955 Serial No. 479,868 1 Claim. (Cl. 260-485) This invention relates to lubricating oil compositions and more particularly-to synthetic lubricating oil com- 3 positions containing esters of dibasic acids. Still more particularly, the invention relates to esters of mixtures of dibasic acids, which ester mixtures are useful as syn 5 atent a 2,837,562 r62 Patented June s, 1958 X represents residues of a mixture of C dibasic acids comprising a major proportion of wethyl suberic acid; and y and z are numbers of 0 to 6 3 a A particularly preferred mixture of'C dibasic acids comprises about 60 to 90% by weight of tat-ethyl suberic acid, about 5 to by weight of a,a'-'diethyladipic acid and about 5 to 15% by weight of sebacic-acid. These mixtures of C dibasic acids may be utilized to prepare thetic lubricants having excellent low temperature perthe lubrication of engines which are subjected to high temperatures such as-combustion turbine engines, particularly those of the prop-jet type. Mineral oil lubricants containing added viscosity index improvers, thickeners or other highly non-volatile additives are undesirable for use in such engines because of the tendency to leave a residue which accumulates and interferes with the operation of the engine. Particularly desirable esters, including diesters and complex esters, which are useful as synthetic lubricants, have been prepared heretofore utilizing sebacic acid as one of the reactants in the esterii'ication reaction. Complex esters of this type are described, for example, in U. S. Patents No. 2,575,195 and No. 2,575,196.

It has now been found that esters having improved lubricating properties may be prepared from a mixture of C dibasic acids. The new esters of this invention are superior in certain aspects to esters prepared from a single dibasic acid component, such as sebacic acid. More particularly, it has been found that esters prepared by esterifying a mixture of C dibasic acids comprising a 7 major proportion of a-cethyl suberic acid have superior low temperature properties, especially pour points. The new ester compositions of this invention are suitable for use as plasticizers and the like and particularly as synthetic lubricants.

The novel ester compositions of this invention which have lubricating properties have the sum formula where A represents residues selected from the group consisting (1) Alcohol radical -[Xglycol radical-l (2) 'Monobasic acid radical-glycol radical [-Xglycol radical] B represents residues selected trom the group consisting (1) Alcohol radical (2) Glycol radical-monobasic acid radical diesters (i. e. alcohol radicalX-alcohol radical) as 'i well as complex esters in accordance with thisinve'ntion.

Diester compositions of this invention which have lubricating properties havethe sum formula Where A and B represent residues of monohydric alcohols and X represents residues of the mixture of C dibasic acids.

The following five general types of complex esters may be prepared in accordance with this invention by employlug mixtures of C dibasic acids:

Type I.--Mon0basic acid-glycol-(dibasic acid-glycol) mono'ba'sic acid This complex ester may be represented by the following structural formula:

wherein R and R are the alkyl radicals of the monobasic acids, R and R are the alkyl radicals from the glycols, R is the alkyl radical of the mixture of C dibasic acids, and n is an integer of 1 to 6. i

The esters of this type may be prepared by admixing the calculated amounts of the various compounds and carrying out a straightforward esterification reaction. The reaction conditions are continued with an occasional sample of the product being tested for acidity until a desired minimum acidity is attained.

Type II.-Alcolz0l-dibqsic acid-(glycol-dibasic acid) alcohol This material may be represented by the following formula:

wherein R and R are the'combining radicals of the alcohol, R and R are the alkyl'radicals of the C dibasic acid mixture, R is the alkyl radical of the glycol, and n is an integer of 1 to 6. 7

These esters are prepared in the manner similar-to those of Type 1.

Type III.Alc0h0l-(dibasic acid-gIycOD -m n basic acid These esters are prepared by reacting the C dibasic wherein R is the combining radical of the aliphatic alcohol, R the alkyl radical of the C dibasic aci-d mixture, R the alkyl radical of the glycol, R the alkyl rad-i cal of the monobasic acid, and n is an integer of 1 to 6.

The preparation of these ester materials is specifically set out in U. S. Patent No. 2,575,195.

Type I V.-Alcohol-dibasic acid-(glycol-dibasic acid),-

alcohol These materials may be said to have the general formula: g

alcohol, R and R the alkyl radicals ,of the C dibasic acid mixture, R is the alkyl radical of the glycol, and n is an integer of l to 6.

It will be noted that the esters of Type IV have the same structural formula as Type 11. However, these complex esters are prepared by reacting an alcohol with the C .dibasic acid mixture under such conditions that a half ester is formed and reacting two moles of such ester with one mole of a glycol; The preparation of this type of synthetic ester lubricating oil is set out in detail in copending application Serial No. 52,429, now Patent No. 2,703,811 which has been reissuedto Reissue No. 24,287

Type V.-Monobasic acid-glycol-(dibasic acid-glycol) m onobasic acid 7 These synthetic esters may be said to have the general formula: V

R CO--R -(OOCR COOR ),,OOCR wherein R and R are the alkyl radicals of the monobasic acid, R and R are the alkyl radicals of the glycol, R

. is the alkyl radical of the C dibasic acid mixture, and

n is an integer of 1 to 6.

It will be noted that these synthetic esters are the same as those appearing above under Type I except that this type is prepared by reacting a monobasic acid with a glycol under such conditions that a half ester is formed and reacting two moles of such ester with one mole of the C dibasic acid mixture. The details of the preparation of this type of synthetic ester are set out in U. S. Patent No. 2,575,196.

As was set out above, these complex ester materials are prepared by combining alcohols, monobasic acids, C dibasic acid mixtures, and glycols in various fashions. In preparing such complex ester compositions, mixtures of difierent molecular weight complex esters are generally formed along with a minor portion of simple ester. Thus more specifically esters having y and z integers (in the aforementioned general formula) varying from 0 to about 6 may be formed.

Monohydric alcohols containing 1 to 20 carbon atoms may be utilized to prepare the complex ester compositions of this invention. Preferably, the monohydric alcohols are aliphatic primary alcohols containing no oxygen or sulfur atoms and having from about 6 to 10 carbon atoms per molecule. The monohydric alcohols which may be employed are typified by the following:

Methyl alcohol Ethyl alcohol n-Butyl alcohol 2-ethylbutyl alcohol N-hexyl alcohol n-Octyl alcohol Z-ethylhexyl alcohol Cetyl alcohol Oleyl alcohol Ethylene glycol mono-n-butyl ether Ethylene glycol mono-2-ethylbutyl ether Ethylene glycol mono-Z-ethylhexyl ether Ethylene glycol mono-tert.-octyl ether fl-n-Butylmercaptoethanol B-Tert.-octylmercaptoethanol fl-n-Dodecylmercaptoethanol Diethylene glycol mono-n-butyl ether Diethylene glycol mono-Z-ethylbutyl ether Diethylene glycol mono-Z-ethylhexyl ether j Propylene glycol mono-butyl thioether H 7 .4 Propylene glycol mono-tert.-octyl thioether Propylene glycol mono-n-dodecyl-thioether n-Butylmercaptoethoxyethanol Tert.-octylmercaptoethoxyethanol n-Dodecylmercaptoethoxyethanol n-Butylmercaptopropoxypropanol Tert.-octylmercaptopropoxypropanol n-Dodecylmercaptopropoxypropanol Propylene glycol mono-n-butyl ether Dipropylene glycol monomethyl ether Dipropylene glycol monoethyl ether Dipropylene glycol mono-n-butyl ether Tripropylene glycol monomethyl ether Tripropylene glycol monoethyl ether Tripropylene glycol mono-n-butyl ether Propylene glycol monoisopropyl ether Dipropylene glycol monoisopropyl ether Tripropylene glycol monoisopropyl ether Many of the above listed ether alcohols, formed by the reaction of ethylene oxide or propylene oxide with aliphatic alcohols, are known in the industry as Dowanols, Carbitols, or Cellosolves.

A group of alcohols especially adapted for use in connection with the present invention are the so-called Oxo" alcohols, prepared by the well-known 0x0 synthesis. This process involves the catalytic reaction of olefins with carbon monoxide and hydrogen at elevated temperatures of about 300 to 400 F. and pressures of about 2500 to 4000 p. s. i. g. to form, particularly in the presence of cobalt catalysts, aldehydes having one carbon atom more than the olefinoriginally used. The aldehyde is catalytically hydrogenated to the corresponding alcohol which is recovered as an overhead product by distillation of the reaction mixture. The distillation residue, i. e., the socalled Oxo-bottoms, is rich in by-product alcohols of higher molecular weight. This residue may also be employed.

While the exact composition of all these alcohols is not known, it is well established that they are mixtures of primary alcohols, at least a substantial proportion of which is of the branched-chain type. product consists of a mixture of such alcohols averaging 1 carbon atom more than the olefin originally fed to the Oxo synthesis. Oxo alcohols containing in the range of about 6 to 10 carbon atoms are especially preferred for the purposes of the present invention.

Esters having excellent properties for the purposes of this invention may be prepared from Oxo alcohols produced by reacting polymers and oopolymers of C and C monoolefins in the presence of oxonation catalysts as described above. Suitable mixtures of these monoolefins are readily available in refinery gases, andprocesses for their conversion into liquid copolymers are well known in the art. In accordance with the most widely used of these processes, the olefins are contacted in liquid phase with a polymerization catalyst comprising phosphoric acid supported on kieselguhr. Other similar processes use as catalyst silica gel impregnated with phosphoric acid, or sulfuric acid, Friedel-Crafts catalysts, activated clays, and others. Polymerization conditions in the presence of phosphoric acid catalysts include temperatures of about 300 to 500 F. and pressures of about 250 to 5,000 p. s. i. g. The olefinic feed stocks normally contain about 15 to 60 mol percent of propylene, about 0.5 to 50 mol percent of butylenes and from 0.1 to 10 mol percent of isobutylene, the remainder being saturated hydrocarbons The overhead alcohol Other O'xo alcohols are believed to have compositions generally analogous to that specified above, the chain lengths and degree of branching depending on the type of zolefins used? For example, the Oxo alcohols derived from vtripropylene are believed to be predominantly a mixture-of various isomeriotrimethyl heptanols. It is noted thataeven when pure straight-chainolefins are-used as the starting materials the alcohols obtained consist predomin'afntlyof branched-chain compounds. I

The glycols employed in preparing the esters ofthe present invention include ethylene glycol and any of the parafiinic homolognesfofithe same containing up to 18 carbon atoms. These may include, for example,ethylene glycol, propylene glycol, butylene glycols,''p'inacon'e, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, and the like. Since the glycols may also contain oxygen or sulfur atoms, compounds such as diethylene glycol, tr-iethyle'ne glycohthe polyethylene glycols of the formula V HO(CH CH O),,CH CH OH where n is lto 26, andthepolypropylene ,glycols'of the general formula v R1 R2' R1 R2 Ho(dHdHo ,.dH- 1HOH where either R or R is a methyl group and theo the r is hydrogen, and where n is 1 to 20, may likewiseibe em-: ployed. Glycols containing sulfur atoms in thioether linkages may also be employed, and theseinclude such compounds as thiodiglycol and 1,2-bis(2-hydroXyethylmercapto)ethane. There also may be used glycols containing both oxygen and sulfur in similar linkages; such a compound is bis-( 2-( Z-hydroxyethoxy) ethyl) sulfide.

venti-on are preferably aliphatic and saturated and may contain about 1 to 22 carbon atoms and preferably contain about 2 to carbon atoms per molecule. Among the monobasic acids which maybe employed in the preparation of the esters of the present invention, the follow- The monobasic,carbcxylicacids useful in the present in- 1 ing maybe listed as illustrative: Aceticacid Propionic acid Butyric acid I range of about 300 to Valerie acid Caproic acid Caprylic acid Pelargonic acid Capric acid Laurie acid Palmitic acid Stearic acid 'Oleic' acid fl-Methoxypropionic acid B-Ethoxypropionic acid fl-TerL-octoxyprdtaionicacid fl-Ethylmer'c'aptopropionie. acid 13-Tert.-octylmercaptopropionic 1 acid S-Tert-d0decylmercaptopropionic acid The esters of this inventionareprepared from a mix. ture of C dibasie acids comprising a major proportion of u-ethyl suberic acid. A preferred mixture of C dibasic acids comprises about 60 to by weight of. 04. ethyl suberic acid, about 5' to 2 5% by weight of a,qc'diethyl adipic acid and about 5 to 15% by weight of sebacic acid. It will be understood ,thatester compositions of this invention may be prepared by separately forming individual esters using a single C dibasic acid and then subsequently combining these esters to form; ester mixturesin accordance with this invention. However, in the preferred form of the present invention a mixture of these C dibasic acids is esterified since such mixtures of C dibasic acids may be relatively inexpensively prepared. For example, butadiene'obtained from petroleum. may be polymerizedto a dimer mixture which may-then be'converted to mixtures of Cmidibasic acids by reaction of the d aifl. mixtur w t HQ fo lowed y yd ly i or bi Wa W h HC nd .NaCN f l o ed by hydrolysis or byythe oxonation of 3 thedirner diolefin followed by oxidation to the acid mixture,

The molecular'weight' of'the'ester molecules of. the invention preferably should be. at least about 300 and the viscosity at 210 F, preferably should not be greater than about a es't i rci prod sthav n good lubricating properties. "Generally, the esters of this. invention will contain-in thef'ra n ge ofabout 2 0 to l30 carbon atoms per molecule and preferably contain about 24 to carbon atomspermoleculep The average molecular weight of the complex esters preferably is in the 0 In d ti l to be us lf as synthetic lubricants, thee'sfters of this invention-are useful as plasticizers, components of plasticizers, and the like. The esters a're particularly useful I in. synthetic lubricating compositions because of the r excellent low temperature performance. Generally, 'itlis desired that ester compositions which are utilized in synthetic lubricant blends for jet aircraft have the following ranges of properties: i ASTM flash poinL; 140o to 550 F. ASTM pour point Below: -.35 'to 75 F. Kinematic 'vis./ 21 0 F- 3 to 1 1 'cs'.

The esters of this invention maybe employed in lubri eating oil compositions containing fotherilubricatingioil conventional methods using acid, alkaliand/or clay orv other agents such as aluminum chlo'ride,.or they may be extracted oils produced, for example; by solvent .extraction with solventsof the type of phenol, sulfur dioxide, 'furfural, dichloroethyl ether, nitrobenzene, croton-: aldehyde, vetc. Preferably, the mineral lubricating oil' base stocks have been dewaxed by any of the Well-known dewaxing methods such as solvent (propane, methyl ethyl.

ketone, etc.) dewaxing or by utilizing plate and frame presses with chilling. The mineral lubricating oils generally have viscosities in the range of about 40 to 150 seconds Saybolt at 210 F.

Also other synthetic lubricating oils having a viscosity of at least 30 SSU at 100 F. may be used in admixture with the esters of the present invention. Examples of these other synthetic lubricating oils include esters of monobasic acids (e. g. ester of C Oxo alcohol with C Oxo acid, ester of C Oxo alcohol with octanoic acid, etc.), esters of dibasic acids (e. g. di-nonyl adipate, etc.), esters of glycols (e. g. C Oxo acid diester of tetraethylene glycol, etc.), complex esters (e. g. the complex ester formed by reacting one mole of sebacic acid with two moles:v of tetraethylene glycol and two'moles of Z-ethylhexanoic acid;.the complex ester formed by reacting one mole of tetraethylene glycol with two moles of sebacic acid and two moles of 2-ethylhexanol; the complex ester formed by reacting together one'mole of azelaic acid, one moleof tetraethylene glycol, one mole of C Oxo al cohol, and; one mole of c, Oxo acid), esters of phosphoric acid (e. .g. the ester for'm'edby contacting three moles of the mono methyl ether, of ethylene glycol with one mole of phosphorus oxychloride, etc.), halocarbon oils (e. g. the polymer of chlorotrifluoroethylene containing twelvefrecurring units of chlorotrifluo roethylene), alkyl silicates (e. g. tetra-Z-ethylhexyl silicate, hexa-C Oxo disiloxane), silicones (e. g. methyl polysiloxanes, ethyl polysiloxanes, methyl-phenyl polysiloxanes, ethyl-phenyl polysiloxanes, etc.), sulfite esters (e. g. ester formed by reacting one'mole of sulfur oxychloride with two moles of themethyl ether of ethylene glycol, etc.), carbonates (e. gthecarbonate formed by reacting C Oxo alcohol with ethyl carbonate to form a half ester and reacting this half ester with tetraethyl ene glycol), mercaptals (e. g. the .me'rcaptal formed by reacting ZI-ethyl 'hexyl mercaptan with formaldehyde), formals (e. g. the formal formed by reacting C on alcohol withformaldehyde or the formal formed by reacting-2 moles C Oxo. alcohol with two moles formaldehyde to form a hemiformal which is then reacted with one mole tripropylene glycol), polyglycol typef synthetic oils (e. g. the compound formed by condensing butyl alcohol with fourteen units of propylene oxide, etc.), or mixtures of any of the above in any proportions. In general, the esters of this invention may be utilized in lubricating oil compositions in proportions in the range of about 5 to, 100% by volume based onthe total lubricating oil basestoek employed in the lubricating oil compositions.

' Also it may be desirable in mixtures of the diesters and the complex esters prepared I in accordance with this invention to thereby obtain the advantages of each of these two types of esters in a single lubricating'o'il blend.-- Itwill be understood in this connection that'in general there is a significant difference between the properties and characteristics of dieste'rs and complex esters. Thus a number of differentv blends of these two types of esters may be prepared to provide a series of lubricant base stocks which have different volatilities, pour points,viscosity indices, and the like, to thereby provide suitable tailor-made lubricants for different lubricating conditions, e. g; different temperature, different pressure, difie'rent' application, etc. i

The lubricating oil compositions of this invention (which comprise a major proportion of a lubricating oil) may also include minor proportions of conventional additives such as V. I. improvers or thickeners, e. g. polymethacrylates, polyacrylates; extreme pressure agents, e. g. dialkyl acid phosphites; oxidation inhibitors, e. g. phenothiazine; rust inhibitors, e. g. calcium sulfonate, lecithin, Span 80; anti-wear agents, e. g. tricresyl phosphate; and the like, to obtain desired results- The ester compositions of this invention may also be employed as the lubricating many instances .to employ ever, that the examples are given for the purpose of illustration only and are not to be construed as limiting the scope of the present invention in any way.

EXAMPLE I A. PREPARATION on CONVENTIONAL DIESTER A diester of a C Oxo alcohol and sebacic acid was prepared. The C Oxo alcohol was obtained by oxonation of a C olefin fraction obtained by fractionating a p'ropylene-butylene polymer produced by phosphoric acid polymerization. The C Oxo alcohol sebacic acid diester was prepared by heating stoichiometric amounts of the necessary ingredients plus 10% excess C Oxo alcohol, 0.5% NaHSQ, catalyst and 10% heptane water entrainer to a maximum esterification temperature of 2l0-220 C. until all of the water of esterification had been removed or collected in a water trap. The crude ester was then decanted from the catalyst, diluted with a half volume of heptane and washed with dilute sodium carbonate solution before finally stripping to about 200 C. at 8-10 mm.

' B. PREPARATION OF DIESTER OF THIS INVENTION A diester of C Oxo alcohol and a mixture of C dibasic acids was prepared. The C7 Oxo alcohol was the same as that employed in part A of this example. The

mixture of C dibasic acids consisted essentially of the following:

Dibasic acid:

a-ethyl suber e,a'-Diethyl adip 15 Sebacic 1D The diester of C Oxo alcohol'and the mixture of. C dibasic acids was prepared in the manner described above 'for C Oxo sebacatec. PROPERTIES onrrnn mnsrnns The. diesters prepared as above had the following properties:

Oonven Dlester 0! tin this Dlester Invention (Part A) (Part B) Vis.: 210 R, Us 3.2, 2. 93 F.-. 11.3 11.31 40 Solid 1511 -65 F Solid 9186 Pour Point, F 35 -76 EXAMPLE II A. PREPARATION OF CONVENTIONAL COMPLEX ESTER (i. e. 2 moles of the alcohol and 2 moles of the acid per mole of the glycol) plus 20% excess alcohol, 0.5%

Weight, percent 9 NaHSO catalyst and 10% heptane were heated to 210 C. 1111111 101110111 water of reactwn was formed. The

crude ester was then heat treated for 3 hours at 230-240 C; at mm. pressure. The material was then decanted from the catalyst, washed with 10% Na CO washed with heptane-isopropanol-water mixture and then stripped to 160 C. at 10 mm.

B. PREPARATION OF COMPLEX ESTER OF THIS INVENTION A complex ester of C OX0 alcohol, a mixture of C dibasic acids and thiodiglycol was prepared. The C Oxo alcohol was prepared by oxonation of a C propylenebutylene polymer followed by hydrogenation. The heart cut from this process constitutes the C Oxo alcohol and has been described more fully heretofore in this specification. The mixture of C dibasic acids was the same as that used in Example 1, part B. The complex ester was prepared in the same manner as described in Example 11, 7

part A.

6. PROPERTIES OF THE COMPLEX ESTERS The complex esters prepared as described above had the following properties:

Conven Complex tional Ester of Complex this Ester Invention (Part A) (Part B) 6. 92 6. 60 33. 3 36. 2 40 F Solid 18570 Pour Point, F +55 75 D-664 Neut. No 0. 19 0.29 Hydroxyl No 0. 7 1. 0 Sulfur, percent 3. 70 4. 25

It will be noted that the conventional complex ester had a pour point of +55 F. and was solid at a temperature of 40 P. On the other hand, the complex ester of this invention had a pour point below 75 F. and was a liquid at 40 F. In addition, the complex ester described above which was prepared in accordance with this invention has an excellent load-carrying ability making it additionally useful as a jet engine lubricant.

EXAMPLE III A complex ester of C Oxo alcohol, a mixture of C dibasic acids and tetraethylene glycol was prepared. The C Oxo alcohol was the same as that described in EX- ample 11, part B, and the mixture of C dibasic acids was the same as that described in Example I, part B. The complex ester of this example was prepared in the same manner as described in Example II. The complex ester prepared above had the following properties:

Properties:

Kin. vis.

210 F, cs 8.85 100 F 49.9 0 F 2140 -40 F 40,200 Pour point, F 60 It will be noted that the complex ester described above has properties making it useful as a synthetic lubricating oil base stock for synthetic lubricating oil compositions.

EXAMPLE IV A synthetic lubricating oil composition consisting of 10% by volume of the complex ester described in Example II, part B, and 90% by volume of di-2-ethylhexyl sebacate was prepared. This blend was an excellent synthetic lubricant which met the requirements of Govern- 10 ment Specification-MIL-L-7808 for Aviation Gas Tun bine Engine Lubricants as is shown below:

A. PREPARATION OF CONVENTIONAL DIESTER A diesterof a C Oxo alcohol and sebacic acid was prepared. The 0, 0x0 alcohol in this example was ob-' tained by oxonation of a C olefin fraction obtained from the steam cracking of gas oil and containing about of straight chain C olefins, 13% of cyclic C olefins and 7% of branched chain C olefins. The diester was prepared by heating the following ingredients for 3 hours at 185 C. in the presence of 0.5 wt. percent NaHSO catalyst and 0.5 wt. percent phenothiazine oxidation inhibitor and g. heptane water entrainer:

Moles Grams 01 0x0 Alcohol 1 88.8 Excess Alcohol, 20%. 17. 8 Sebacic Acid 1 77. 0

1 Stoichiometric amounts.

The ester product was diluted with 200 cc. of heptane, washed in sodium carbonate and then stripped at C. at 0.14 mm. to give an oily ester product.

B. PREPARATION OF DIESTER OF THIS INVENTION A diester of C7 Oxo alcohol and a mixture of C dibasic acids was prepared. The C Oxo alcohol was the same as that described in part A of this example. The mixture of C dibasic acids was the same as that described in Example I, part B. The diester was prepared in the same manner as described above for C Oxo sebacate (part A).

C. The diesters prepared as above had the following properties:

Conven- Diester of tlonal this Inven- Diester tlon (Part (Part A) B) 2. 83 10. 78 1288 Solid 8811 V. I 163 122 Pour Point, F 15 (-80 D-664 Neut. No 0.18 0.25 Hydroxyl No 0.3 I

It will be noted that the diester prepared in accordance with this invention (part B) had a substantially lower pour point than did the conventional diester (part A), namely -80 F. compared to 15 F.

What is claimed is:

As a new composition of matter having lubricating properties a complex ester composition of (a) two moles of an isomeric mixture of aliphatic, saturated, primary branched chain C alcohols and (5) two moles of an isomeric mixture of C dibasic acids comprising by weight about 75% of ot-ethyl suberic acid, about 15% a,a'-di ethyl adipic acid and about 10% sebacic acid and (c) 5 a 11 one mole of tetraethylene glycol typified by the general 2,570,037 formula: 1 i 2,575,196 R OOCR COOR OOCR CO0-R I 2628974 wherein R and R are radicals of the alcohol, R and R 5 are alkyl radicals of dibasic acid and R is the radical of 666,697

the glycol. a

3 References Cited in the tile of this patent UNITED STATES PATENTS 10 2,499,983 Beave'rs Mar. 7, 1950 2,499,894 'Beavers et a1 Mar. 7, 1950 12 Smith et al. Oct. 2, 1951 Smith Nov. 13, 1951 Sanderson Feb. 17, 1953 FOREIGN PATENTS Great Britain Feb. 20, 1952 OTHER REFERENCES Ind. & Eng. Chem. 39, No. 4, pages 484-497, pages 484-487 pertinent.

Ind. & Eng. Chem. 45, N0. 8, pages 1766-1775, pages 1769-1773 pertinent. 

